1. Field of the Invention
The present invention relates to an improved droplet dispensing closure which is connectable to a bottle neck opening and preferably, but not exclusively, a bottle containing a medicinal liquid. The droplet closure has a dispensing tube in which at least a dispensing section thereof is of constant inner diameter and wherein droplets can be dispensed, as soon as the bottle is inclined above the horizontal, at a rate which is slow enough to permit the counting of individual drops emitting from the dispensing tube.
2. Description of Prior Art
Various closure members are known for dispensing liquid from a bottle at a drip feedrate. A product similar to that of the present invention is described, for example, in German Patent DE 29 49 223 dated Sept. 19, 1980. The present invention is an improvement of such closure and wherein drops can be dispensed as soon as the bottle is positioned at an angle above horizontal, whereas in the reference, it is necessary to place the bottle to a vertical position in order for the closure to start dispensing. The inner diameter of the drip tube is often tapered and the drops are not of even size and air can infiltrate through the drip tube.
Another disadvantage of the prior art closures is that when the sealing cover is placed onto the closure, it often damages the dispensing tube or the air vent tube, thereby affecting the operation of the dispensing closure. Also, the cover often touches the end of the dispensing tube and forces liquid back into the bottle. This could result in contamination as the liquid forced back in was exposed to outside air and light. Still further, the prior art designs often admit too much air into the bottle at an uneven rate, thereby resulting in an uneven dispensation rate.
It is desirable that the dispensing rate be slow and constant whereby the drops can be easily counted as they are dispensed. This is particularly important when dispensing a medical product. It has also been found that it is important to maintain, at least the dispensing section of the dispenser tube of a constant diameter, in order to achieve an accurate drop size in dispensing the fluid.